It was a Google app that no one used—until they could take a selfie with it.

Although Google launched the app in 2016, it hadn’t received much traction until a portrait feature was added, proving that the human face and social media are potent ingredients for any organization hoping to go viral.

NPR reported:

It works like this: iPhone or Android users must download the app, then find the “Is your portrait in a museum?” function and take and submit their photo. Google sifts through the thousands of paintings in its database and using its computer vision software makes a match alongside a percentage of how well the two images resemble each other. (There is no explanation given about the supposed science behind this.)

Users seemed not to care whether the company could prove the science behind its matching algorithm. Instead, the interactive app gained traction quickly.

NPR continued:

The metric site App Annie said Google Arts & Culture was the No. 1 free app over the weekend. And by Monday, it was still holding on to the spot.

Perhaps users can’t resist the vain pleasure of seeing and showcasing their own visages reflected back in a famous work of art.

Although most brands don’t have the computing power or engineering departments to replicate Google’s face-matching software, there are some universal rules about going viral on social media that can be gleaned from its popularity.

Here are four lessons for brand managers looking to replicate the Google app’s viral success:

1. Make it interactive.

Google’s success with its art app is built on user interaction, with users uploading pictures and then sharing their results. By asking users to invest a little time and effort, Google has created an experience rather than a quick hit, such as a meme or blog post.

Would the app have gone viral matching images of your household furniture? It seems unlikely.

3. Choose a unique hashtag.

Though you might get lucky and go viral without a well-crafted hashtag, finding all the social media posts that connect to your content will be impossible. A good hashtag indexes social media posts and can be a shortcut for finding the content most relevant to your brand or organization.

Although Google’s hashtag #googleartsandculture seems too long, it is precise and unique to the app. If an extra word or two will help your hashtag stand out from the noise, it’s worth it.

4. Provide easily shareable content.

Any brand manager hoping to go viral should put thought into the content. Whether it’s a filter or the results of a personality quiz, it should be an easy click and grab to share it to social media, or users might decide it’s not worth the effort.

Google designed its template to include the art portrait and the user selfie in a clean format. Without its simplicity, the feature might never have engendered the current social media frenzy.

Have you tried the app, Ragan/PR Daily readers? Let us know which portrait you resemble.